1. Field of the Invention
This invention relates to a tape-printing apparatus for printing on a tape, and more particular to a tape-printing apparatus which is capable of setting the length of a marginal area defined between a leading cutting position on a tape and a print-starting position on the same.
2. Prior Art
Recently, there comes into use a tape-printing apparatus called a tape printer or a label word processor. According to a tape-printing apparatus of this kind, printing is effected on a front surface of a portion (hereinafter referred to as a "label portion") of a continuous tape, and the label portion is cut off to a desired length. Then, a release paper is peeled off the reverse side of the label portion to thereby reveal an adhesive surface of the label portion, whereby the label portion is made attachable to a desired place as a label or the like. The tape-printing apparatus rapidly comes into wide use as a home-use printing apparatus because of the ease of operation and a low price.
On the other hand, higher levels of function are demanded of this kind of tape-printing apparatus, as well. For example, an ordinary tape-printing apparatus requires a certain distance between a printing operation position of a print head thereof and a cutting operation position of a tape cutter thereof for cutting a continuous tape, due to limitations of a mechanism of the apparatus. Accordingly, a leading margin (i.e. margin at a leading end of a label portion in the direction of feeding of the continuous tape) is necessarily formed on the label portion which corresponds to the distance between the cutting operation position and the printing operation position in the apparatus. However, this leading margin has a length larger than desired of a label by the user. To overcome this inconvenience, the tape-printing apparatus is demanded of a capability of automatically forming a leading margin of the label portion to a length desired by the user. A tape-printing apparatus having the function which meets this demand by the user has been proposed e.g. by Japanese Laid-Open Patent Publication (Kokai) No. 5-84994.
According to the proposed tape-printing apparatus, when the length of a leading margin of a label portion of a tape is set, a position of a leading edge of the leading margin, i.e. a cutting position on the leading end side of the tape where the tape is cut is determined with reference to a print-starting position on the tape where printing is started, and then the label portion is printed by driving a thermal head while feeding the tape to a cutting operation position of a tape cutter. Then, a tape feed motor is stopped to temporarily place the tape in position for cutting. Then, the tape cutter is operated to cut the tape to thereby form the leading margin of the label portion to the length set by the user.
When the leading edge of the label portion has been cut, the driving of the tape feed motor and printing by the thermal head are resumed. When the printing of the label portion is completed, the tape feed motor is further driven until a position of a trailing edge of a trailing margin which is set to a predetermined length similarly to the leading margin, i.e. a cutting position on the trailing end side of the tape where the tape is cut is brought to the cutting operation position, whereupon the label portion is cut off from the tape. Thus, the label is made which is formed with the leading and trailing margins having desired lengths, as a portion preceding the print-starting position on the tape from which a printed portion starts and a portion following a print-terminating position at which the printed portion terminates, respectively.
However, the conventional tape-printing apparatus suffers from the following inconveniences: When the tape cutter operates, the tape is caught between blades of the tape cutter to be pulled forward, resulting in displacement or an undesired forward shift in position of the tape. Further, when the feeding of the tape is suddenly stopped, the reactionary force against stoppage accumulated within a tape-driving mechanism still feeds the tape forward, resulting in an undesired forward shift in position of the tape. Due to these undesired forward shifts in position of the tape, there can be formed a so-called spaced-dots area between dots printed immediately before cutting the tape and dots printed after the printing is resumed. This results in cleaved printed letters or the like, which degrades the quality of print.
On the other hand, if the feeding of the tape is suddenly accelerated, the driving force is absorbed by the tape-driving mechanism of the apparatus to delay the feeding of the tape, which causes displacement or an undesired backward shift in position of the tape. That is, in this case, there can be formed a so-called jammed-dots area between dots printed immediately before cutting of the tape by the tape cutter and dots printed after the printing is resumed. This also degrades the quality of print.